LAUSR

BACKGROUND Successful achievement of randomized controlled trials (RCTs) is dependent on the acquisition of informed consent (IC) from patients. The aim of this study was to prospectively calculate the proportion of participation in a surgical RCT and to identify the reasons for failed acquisition of IC. METHODS A 50-insitution RCT was conducted to evaluate oncological outcomes of open and laparoscopic surgery for stage IV colon cancer (JCOG1107: UMIN-CTR 000000105). The success rate of obtaining IC was evaluated in eight periods between January 2013 and January 2021. In addition, reasons for failed acquisition of IC were identified from questionnaires. RESULTS In total, 391 patients were informed of their eligibility for the trial, and 168 (42%) were randomly assigned to either the laparoscopic surgery group (n = 84) or open surgery group (n = 84). The success rate of IC acquisition ranged from 33 to 58% in three periods. The most common reasons for failed IC acquisition were the patients' preference for one approach of surgery based on recommendations from referring doctors and family members, and anxiety/unhappiness about randomization. CONCLUSIONS The success rate of acquiring IC from patients for an RCT of laparoscopic versus open surgery for stage IV colon cancer was lower than the expected rate planned in the protocol. To obtain the planned rate, investigators should make efforts to inform patients and their families about the medical contributions a surgical RCT can make and recognize that the period in equipoise may be limited.